buildbot exception in MacPorts on ports-10.12_x86_64-watcher

[buildbot at macports.org]

The Buildbot has detected a build exception on builder ports-10.12_x86_64-watcher while building macports/macports-ports. Full details are available at:
    https://build.macports.org/builders/ports-10.12_x86_64-watcher/builds/25414

Buildbot URL: https://build.macports.org/

Buildslave for this Build: ports-10.12_x86_64

Build Reason: The SingleBranchScheduler scheduler named 'ports' triggered this build
Build Source Stamp: [branch master] e5f02483365a1df0e393c385647655ed12daadaf
Blamelist: Carles Fernandez <carles.fernandez at gmail.com>

BUILD FAILED: exception

Sincerely,
 -The Buildbot